Secondhand smoke is a potential risk of developing asthma

Children are more likely to develop asthma if their father was exposed to second-hand smoke as a child, according to a study published today in european journal of respiratory.

Led by researchers from the University of Melbourne, Mr. Jiacheng Liu and Dr. Dinh Bui, the study also showed that children’s risk of developing asthma is higher if their father was exposed to second-hand smoke and became a smoker.

The researchers say their findings highlight how smoking can harm the health of not only smokers and their children, but also their grandchildren.

The study was based on data from the Tasmanian Longitudinal Health Study (TAHS), led by Professor Shyamali Dharmag at the University of Melbourne.

TAHS began in 1968 and is one of the largest and longest-running continuing respiratory studies in the world.

In this study, researchers studied 1,689 children who had grown up in Tasmania and their parents and paternal grandparents.

They compared data on whether children developed asthma at age seven with data on whether fathers grew up with parents who smoked when they were under 15. It also included data on whether the parents were current or former smokers.

Mr Liu said: “We found that children’s risk of non-allergic asthma increased by 59 per cent if their parents were exposed to second-hand smoke in childhood, compared to children whose parents were not exposed.

“The risk was higher, at 72 percent, if the fathers were exposed to second-hand smoke and continued to smoke themselves.”

Dr Bowie said the findings show how the harm from smoking can have an impact not only on smokers, but also on their children and grandchildren.

“For men who were exposed to second-hand smoke in childhood, our study suggests that they can still reduce the risks to their children, if they avoid smoking,” said Dr. Bowie.

Although the researchers cannot be sure how this damage is passed down through generations, Professor Darmag said they believe it may have something to do with epigenetic changes.

This is where factors in our environment, such as tobacco smoke, interact with our genes to modulate their expression. These changes can be inherited but may be partially reversible for each generation.

Tobacco smoke can cause genetic changes in the cells that will produce sperm when boys are older. These changes can then be passed on to their children.”

The researchers will now investigate whether the risk of developing asthma persists in adult life and whether parents who were exposed to second-hand smoke during children transmit any increase in allergies or other lung diseases to their children.

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